The use of water-based emulsion polymer systems as protective and decorative coatings for many types of surfaces has become widespread. The so-called latex paint is commonly used by individuals in homes and industrially. While oil-based systems are known to retain their adhesive properties under wet or humid conditions, a characteristic called "wet adhesion," the tendency of many water-based coating to lose their adhesive properties when wet has limited the usefulness of such coatings. This is particularly true for paints based on vinyl-acrylic or all acrylic latices which otherwise are attractive as paint vehicles.
Paints intended for outdoor use are frequently exposed to moisture and humidity, as are paints used on interior surfaces in wet or humid atmospheres, such as in bathrooms and kitchens. Good wet adhesion is an important attribute of paints applied to those surfaces and others where resistance to water and abrasion is important, as where paints are exposed to washing or scrubbing, and where water-based paints are applied to glossy surfaces. In these situations, the need for improved wet adhesion of aqueous emulsion polymer systems is particularly great.
The art has recognized the problem of loss of adhesive properties in latex paints when wet, and a variety of additives to latex systems to improve wet adhesion has been proposed. For example, U.S. Pat. No. 3,356,655, issued on Dec. 5, 1967, and U.S. Pat. No. 3,509,085, issued on Apr. 28, 1970, disclose a number of ethylenically unsaturated hydroxy-functional amines which are said to be useful in improving adhesion and water resistance of latex paints. In addition, U.S. Pat. No. 4,111,877, issued on Sep. 5, 1978, discloses certain imidazolidinone derivatives which are said to improve the adhesive properties of latex paint.
It has now been found that latex-containing surface coatings and coating compositions having excellent wet adhesion properties can be produced by including in the monomer system one or a mixture of novel polymerizable monomers. In particular, the new compounds of this invention have been found to be especially useful in water-based latex-containing paints and can also be employed as comonomers in solution polymers.
U.S. Pat. Nos. 4,487,940 and 4,526,915 (Sekmakas et al.) disclose an acrylate or methacrylate functional copolymerizable monomer which serves to improve the adhesion of emulsion polymers is disclosed. This monomer is the adduct formed by reacting an aminoalkyl alkylene urea with about 0.9 up to about 1.5 molar proportions of a saturated monoepoxide to consume most or all of one of the two amino hydrogen atoms available, and then reacting with about 0.8 up to about 2.0 molar proportions of a monoisocyanate having a single acrylate or methacrylate group in the presence of at least 0.02%, based on the total weight of the reactants present, of an inhibitor, such as hydroquinone or phenothiazine, which retards the free-radical polymerization of ethylenic unsaturation.